Did the activation change this year?

i have always purchased this and then downloaded and activated it on my pc.

Then i would download and activate on my mom's pc.

This year i downloaded it there and logged into my turbotax account and it showed the 16 digit code and then i tried to activate it and it gave me error 605.  Someone is saying that it only activated on PCs that I own.

How do you know what PCs I own???  can it only be activated on 1 PC?   i need some help here.

So, we need to buy this twice if we have a family member living in another house?  This is new. I never had to buy this twice before.